Black Hole Entropy from Horizon Conformal Field Theory

TL;DR

This paper suggests that a two-dimensional conformal symmetry at black hole horizons, with a classical central extension, could explain the universal nature of black hole entropy across different quantum gravity models.

Contribution

It proposes that horizon conformal field theory, characterized by a classical symmetry, underpins the universal entropy of black holes, linking classical relativity to quantum results.

Findings

Evidence for a 2D conformal symmetry at the horizon.

Classical central extension explains the density of states.

Supports a universal microscopic origin of black hole entropy.

Abstract

String theory and ``quantum geometry'' have recently offered independent statistical mechanical explanations of black hole thermodynamics. But these successes raise a new problem: why should models with such different microscopic degrees of freedom yield identical results? I propose that the asymptotic behavior of the density of states at a black hole horizon may be determined by an underlying symmetry inherited from classical general relativity, independent of the details of quantum gravity. I offer evidence that a two-dimensional conformal symmetry at the horizon, with a classical central extension, may provide the needed behavior.